Most commercial and industrial systems use multiple membranes arranged in parallel to provide the required quantity of water. The processed water from the first stage of treatment can then be passed through additional membrane modules to achieve greater levels of treatment of the finished water. The reject water can also be directed into successive membrane modules for greater efficiency, though flushing will still likely be required when concentrations reach a level where fouling is likely to occur.
High-pressure industrial units typically provide from 10 to thousands of gallons of water per day, with an efficiency of 1-9 gallons of reject water per gallon of treated water. Water purity can be as high as 99%. These systems tend to be larger and more complicated than low-pressure systems, and this is reflected in their cost. Commercial and industrial units can range in cost from $1,000 to tens of thousands of dollars for a large, multi-module unit that can provide desalinated drinking water for a resort facility or water bottling plant.